From mboxrd@z Thu Jan 1 00:00:00 1970 From: Takashi Iwai Subject: Re: [Alsa-user] Re: audio format TYPE II and TYPE III descriptor support Date: Fri, 09 May 2003 11:36:19 +0200 Sender: alsa-devel-admin@lists.sourceforge.net Message-ID: References: Mime-Version: 1.0 (generated by SEMI 1.14.4 - "Hosorogi") Content-Type: text/plain; charset=US-ASCII Return-path: In-Reply-To: Errors-To: alsa-devel-admin@lists.sourceforge.net List-Help: List-Post: List-Subscribe: , List-Unsubscribe: , List-Archive: To: Jaroslav Kysela Cc: alsa-devel List-Id: alsa-devel@alsa-project.org At Fri, 9 May 2003 11:11:48 +0200 (CEST), Jaroslav wrote: > > On Fri, 9 May 2003, Takashi Iwai wrote: > > > At 09 May 2003 09:22:28 +0200, > > christopher cuse wrote: > > > > > > Good Day, > > > > > > the following is a snip from > > > > > > /alsa-driver-0.9.3a/alsa-kernel/usb/usbaudio.c > > > > > > /* FIXME: needed support for TYPE II and III */ > > > if (format_type != USB_FORMAT_TYPE_I) { > > > snd_printd(KERN_INFO "%d:%u:%d : format type %d is not > > > supported yet\n", > > > dev->devnum, iface_no, altno, format_type); > > > return -1; > > > } > > > > > > > > > If a usb card has TYPE II or TYPE III, is there a work around? > > > > my current version already supports these formats but still under > > debugging. (also, for using TYPE II, we need a special tool. the > > current audio apps support only linear/float formats.) > > Type II contains MPEG formats? yes, so far, MPEG (I,II and each layer) and AC3 are defined as the standard TYPE II. i'm testing an SB Extigy, which supports AC3. perhaps a newer version of Creative's USB device will support MPEG (according to their ad). for TYPE III, i'm using the normal linear S16_LE. it's in fact IECxxx but it's used as 16bit 2 channels. the support of TYPE II needs, however, still many works. - MPEG means not only single format but many different ones, layer 1-3, MPEG I and II (and later). use of subformat is necessary to distinguish it? (if we use subformat, snd_pcm_area_xxx needs also the argument for subformat..?) - there is no format defined for AC3 yet. (SPECIAL is used for testing now.) - moreover, how do we define the "frame size" of the format? is it defined as the (alignment of) period size, or the ALSA frame bit size? Takashi ------------------------------------------------------- Enterprise Linux Forum Conference & Expo, June 4-6, 2003, Santa Clara The only event dedicated to issues related to Linux enterprise solutions www.enterpriselinuxforum.com